Synchronized secondary clock movement



June 10, 1941. L STQNE 2,244,811

SYNCHRONIZED SECONDARY CLOCK MOVEMENT Filed Aug. 19, 1939 2 Sheets-Sheet1 NVENTOR fix/m 2. 2%,

H/J ATTORNEYS June 10, 1941. L B. STONE 2,244,811

SYNCHRONIZED SECONDARY CLOCK MOVEMENT Filed Aug. 19, 1939 2 Sheets-Sheet2 INVENTOR. Z. a) 6. d/i- BY fT/o 444. A rrn/v/wyys'.

Patented June 10, 1941 SYNCHRONIZED SECONDARY CLOCK MOVEMENT Lucien B.Stone, South Orange, N. J., assignor to Self Winding Clock Company,Inc., Brooklyn, N. Y., a corporation of New York Application August 19,1939, Serial No. 290,990

4 Claims.

My invention relates to synchronized secondary clock movements whichreceive at stated periods, such as for instance hourly and on the hour,a synchronizing impulse from the master clock by which the clock isre-set to the correct time in case it should be fast or slow. Re-settingmechanisms for clocks per se are old in the art, and the presentinvention refers rather to a particular mechanism for accomplishing thiseifect in a simple and convenient manner. The particular advantages ofmy novel construction are the possibility of bringing about thesynchroniz ing motion by oniy one single impulse of the synchronizingmovement; further, that only one single magnet with a one-pulse movementis required to accomplish the synchronizing; further, means forpreventing the synchronizing motion when the clock is on time so as toavoid unnecessary wear on the synchronizing elements, and other detailimprovements which will appear from the following description.

My invention'is illustrated in a number of modifications in theaccompanying drawings in which Fig. 1 is a rear elevation of my improvedsyn- Fig. 3 is an exploded perspective of parts K shown in 1 and 2;

Fig. 4 is a fragmentary elevation showing parts of Figs. 1 and 2, inoperated position; and

Fig. 5 is a fragmentary rear elevation of part of the clock'movementshown in.Figs. 1 to 4, illustrating a locking mechanism for holding theratchet wheel locked while the synchronizing arm and parts are returningto normal position.

Referring to Figs. 1 through 4, I represents the front plate of theclock on which the dial (not shown) is mounted and on the rear of whichthe clock movement is mounted which is shown in the rear view of Fig. 1.It is assumed in this modification, as well as in the othermodifications, that the secondary clock is normally operated by means ofelectromagnetic impulses controlled by the master clock and which may,as is the usual practice, occur at minute intervals. For this purpose.as shown in Figs. 1 and 2, the following mechanism is provided. 2represents the clock framein which the minute arbor 3 and the hour clocktrain 3a are journalcd in conventional manner. On the minute arbor 3 isfixed a ratchet wheel 4 which is operated step by step at minuteintervals, for instance in the following manner.

In the lower part of the clock frame 2 is mounted electromagnet 5 whichis energized at these intervals from the master clock, and the armature6 of which is fixed to a feeding lever l pivoted in the clock frame at 8and limited in its outward swing by an adjustable stop 9. The lever isyieldingly pressed against this stop by means of a spring l0 bearingagainst the upper free end of lever l and'seated in an adjusting screwl2 threaded into a standard ll so that the pressure of spring l0 can beregulated. When electromagnet 5 is energized, the lever is swung clock.wise, thereby tensioning spring I0, and as soon as the impulse ceases,the spring throws the lever l counterclockwise against stop 9. On thefree end of feeding lever l is pivotally mounted feeding pawl l4 so thatits left-hand end engages the'teeth of ratchet wheel 4. On feeding leverl is provided a flat. spring [6 which presses against a detent [5 offeeding pawl M, whereby the latter is normally held in engagement withthe ratchet teeth. On clock frame 2 is further pivotally mounted at 20 aretaining pawl arm l8 which is illustrated in detail in Fig. 3. This armis provided with a substantially rectangular portion 36 at the lower endof which extends a detent l9 at right angles to the plane of arm l8, sothat in the position in which arm I8 is mounted, pawl l9 extends acrossthe teeth of ratchet wheel 4 and prevents the latter from moving counterto the direction of the arrow in Fig. 1.

This feeding mechanism, so far described, opcrates-in conventionalmanner as follows: Normally, feeding arm I is in the position shown inFig. 1. As soon as an impulse is received at magnet 5, the arm is swungclockwise and thereby pawl 14 is withdrawn to the right by one tooth sothat it falls into the next tooth, and as soon as the magnet isdeenergized, spring I0 thrusts arm 1 to the left, thereby feeding wheel4 and thus the minute arbor by one tooth counter-clockwise in Fig. 1.

In order to re-set the minute arbor in case it should be fast or slow,the following mechanism is provided. In the upper portion of clock frame2 is mounted an electromagnet 2| which cooperates with an armature 2 lawhich is attached to a re-setting arm 22 normally held by a tensionspring 26 against a stop 21' as shown in Fig. 1. This arm is pivoted inthe clock frame at 23 and is oX-bow shaped at its lower end as shown at24, so that it can straddle at thatend the minute arbor 3. On ratchetwheel 4 is provided a pin 25 in such a position that when it standssymmetrically to the ox-bow when the latter is thrown into the dottedposition, the clock hands are located in the desired set or synchronizedposition, for instance exactly on the hour. If during the time when arm22 is attracted by electromagnet 2i and thrown towards the dottedposition in Fig. 1, pin 25 should be to the right or to the left of theposition shown in Fig. 1, the oX-bow will take the pin along and shiftit into the position shown in Fig. 1 thereby rc-set the clock to theproper time.

In order to re-set the minute arbor, however, the feeding and retainingpawls l4 and It must be released from ratchet wheel 4 so that the lattercan be freely turned by the resetting arm. For this purpose, a releaselink 28 is pivotally attached at fifia to re-setting arm 22, and at itsother end to a release cam 29 which is pivotally attached at 30 to theclock frame. This cam has two functions. First, in normal position asshown in Fig. 1 it prevents feeding pawl M from accidentally beingthrown upwardly during the ordinary feeding motion of the feeding arm Iby means of a detent 3| which is in the position shown in Fig. 1 locatedclosely above detent 34 at the left-hand end of feeding pawl l4 withouttouching the latter so that no friction is encountered thereby. Thus thefeeding pawl can move unhindered to the right, but cannot accidentallybe thrown upwardly. The second function of release cam 29 is exercisedby means of a pin 32 extending across the camshaped surface 33 offeeding pawl I4. Thus if during the re-setting operation re-setting arm22 is moved into the dotted position, link 28 throws re-setting cam 29in counter-clockwise direction and thereby first of all the detent 3|moves away from the transversely bent end 34 of pawl l4 which normallyrests against the teeth of ratchet wheel 4, and secondly pin 32 movesalong 1 the cam surface 33 of feeding pawl I4, thereby throwing thelatter in clockwise direction against the tension of its spring it. Thisposition is shown in Fig. 4. Feeding pawl i4 is arranged in a relationto the rectangular portion 35 of arm l8 such that detent 34 of pawl l4extends through the square opening of rectangle 35 and rests normallyagainst the upper edge thereof, as shown in Fig. 1. Thus if feeding pawlI4 is thrown clockwise by the re-setting setting elements, describedhereinbefore, are 1 such that the release of pawls l4 and E5 fromratchet wheel 4 occurs before the oX-bow 24 encounters re-setting pin25. As soon as the impulse imparted to re-setting magnet 2| ceases,spring 26 pulls re-setting arm 2" back to the left to the position shownin Fig. 1 and the remaining elements also return to the position shownin that figure.

In order that the re-setting operation be not interfered with in caseduring the re-setting operation an ordinary operating impulse should beimparted to magnet 5, feeding arm 7 is locked during the l e-settingoperation by the following expedient. As shown in Figs. 1 and 3, theouter end of holding arm i8 is provided with a detent 3'! turned atright angles to the plane of arm l8. This detent is located in such aposition with respect to a nose I! provided at the outer end of feedingarm I that in normal position of arm |8 feeding arm I can freely move tothe right in case an impulse is received at magnet 5. Thereby nose I!passes above detent 3! and blocks upward movement of arm l8, thuslocking the step wheel 4 against forward, as well as retrogrademovement. If, however, the re-setting operation is in progress duringwhich arm 18 is lifted into the position shown in Fig. 4, detent 31 hasrisen into alignment with nose ll so that if now an ordinary operatingimpulse should be received at magnet 5 which would tend to throw theupper end of arm I to the right, detent 37 prevents this and thus theordinary operating impulse remains ineffective insofar as the feedingmotion of ratchet wheel and the clock movement are concerned. As soon asthe re-setting operation is completed, the detent drops back to thenormal position shown in Fig. 1 so that feeding lever 1 is again free tooperate in accordance with the operating impulses received at magnet 5.

It will be noted from Fig. 4 that there exists a time during which atthe withdrawal of ox-bow "4 from pin 25 (after the re-setting has beenompleted) neither feeding pawl |4 nor retainng pawl E9 is in engagementwith the ratchet eeth of wheel 4. In order to prevent an acci- .entalturning of this wheel during this uncont oiled period by any cause, suchas for instance the weight of the hands or other reasons, and avoid thusa disturbance of the synchronized condition of the clock, the followingmeans are provided which are illustrated in Fig. 5. This figure onlyshows the central portion of the clock movement and it is assumed thatthe ratchet wheel 4 is located above the plane of the drawing Fig. 5. Tothe arbor 3, on which wheel 4 is fixed, is also fixed a holding disk 4|which is provided with a notch 42. On the clock frame l is pivoted at 46a toggle lever 45 which is controlled by a toggle spring 41 fixed toframe I at Ma. The other end of spring 41 is attached to a pin 48provided at the free end of lever Normally, spring 41 holds lever 45against a stop 49, but this lever, due to the toggle joint arrangement,can be swung to the right so that the pin 48 will be thrown against theperiphery of disk 4|. The free end of lever 45 and notch 42 of disk 4|are set in such relation that when pin 43 engages notch 42, the ratchetwheel 4 is in the synchronized position, for instance on the hour asassumed in the present example. To re-setting arm 22 is attached atoggle operating arm 43 which is provided at its end with a wide recess44 within which pin 48 is located. Ordinarily, that is to say, whenre-setting arm 22 is in the position shown in Fig. 1, recess 44 hasmoved the toggle joint into the position as shown in Fig. 5. As soon asre-setting arm 22 is energized by its re-setting magnet 2| and moves tothe right in Figs. 1 and 5, arm 43 also moves to the right and therebythrows the toggle joint with its pin 48 against the periphery of disk4|. As soon as ox-bow 24 has completed the re-setting by moving pin 25in Fig. 1 into the position shown, disk 4| has turned with ratchet wheel4 into such a position that its notch 42 registers with the pin 48 sothat the latter drops into the notch. In that position of the elements,the left-hand wall of recess 44 is nearer pin 48 than the right-handwall. Thus when after the completion of the re-setting operation spring26 pulls re-setting arm 22 towards the left in Figs. 1 and 5, pin 48 isnot'yet pulled out of notch 42 by the righthand wall of recess 44 untilre-setting arm 22 has moved quite a distance towards its normal positionduring which the feeding pawl l4 and the holding pawl I9 have droppedback onto the teeth of ratchet wheel 4, when pin 48 is withdrawn fromnotch 42 and the toggle joint snaps back into the position shown in Fig.5. Thus during the critical period, namely, while neither feeding pawl14 nor holding pawl l9 are in engagement with the ratchet wheel andox-bow 24 has been withdrawn from pin 25, the ratchet wheel is held bypin 48 in the Proper set position until the re-setting mechanism hasbeen restored entirely to its normal position.

In case at the arrival of a re-setting impulse at the hour, the clockshould be exactly on time, it would be unnecessary to operate the entireresetting mechanism. Therefore, in order to prevent such an operationand to thereby save wear and tear on this mechanism, the following meansare provided. On ox-bow 24 is mounted a pin 40 which extends towardratchet wheel 4, and on ratchet wheel 4 is mounted a spring 39 in such aposition that its free end is exactly in line with pin 40 when the clockis on time. Thus if now a re-setting impulse is imparted toelectromagnet 2| and the latter attempts to attract its armature, pin 40impinges against the end of spring 39 and thus prevents ox-bow 24 frommoving toward pin 25 and thus locks the entire re-setting mechanism,

I claim:

1. In a secondary clock movement having a toothed step wheel connectedto a hand arbor, an oscillating feed member bearing a pivoted feed pawlengageable with the teeth of said step wheel, a pivoted stop positionedover said feed pawl at the forward limit of its movement to blockpivotal movement of said feed pawl outward from said step wheel,resetting means for said hand arbor, and means operated by saidresetting means for swinging said stop away from said feed pawl andtilting the latter out of engagement with said step wheel.

2. In a secondary clock movement having a step wheel connected to a handarbor, a feed member having an oscillating movement to feed said stepwheel, means for resetting said hand arbor, and means operable by saidresetting means to block the oscillation of said feed member.

3. In a secondary clock movement, a hand arbor unit, feed means to movesaid hand arbor unit progressively, resetting means engageable with saidhand arbor unit to set the same to a definit position, means for movingsaid resetting means to setting position and back to position of rest,and holding means engageable with said hand arbor unit when it is set tosaid definite position by said resetting means, to hold said hand arborunit while said resetting means re turns to position of rest.

4. In a secondary clock movement, a hand arbor unit comprising a stepwheel, a feed member engageable with said step wheel to move said handarbor unit progressively, a holding pawl coacting with said step wheelto prevent retrograde movement thereof, resetting means engageable withsaid hand arbor unit to reset the same to a definite position, means formoving said resetting means to resetting position and back to positionof rest, means operated by said resetting means to disengage saidholding pawl from said step wheel during the resetting operation, and adetent controlled by said resetting means to lock said hand arbor unitin said definite position during the return of said resetting means toposition of rest.

LUCIEN B. STONE.

